Sheet handling apparatus



Aug. 14, 1951 R. D. OSGOOD 2,564,027

SHEET HANDLING APPARATUS Filed Dec. 5, 1947 8 Sheets-Sheet 1 h ril tl jaij juld I li'weizlor; Emu/v a 05 00;,

FIE 1 Aug. 14, 1951 R. D. OSGOOD 2,564,027

7 SHEET HANDLING APPARATUS Filed Dec. 5, 1947 8 Sheets-Sheet 2 if. o 1; /7 i0 hzueiztal': Emu/v 9. 096000, p wyAw 4, 1951 R. D. OSGOOD 2,564,027

SHEET HANDLING APPARATUS Filed Dec. 5, 1947 8 Sheets-Sheet 5 Inventor: Baum Q 056000,

Aug. 14, 1951 R. D. OSGOOD 2,564,027

SHEET HANDLING APPARATUS Filed Dec. 5, 1947 v 8 Sheets-Sheet 4 FIB-.5-

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Aug. 14, 1951 R. D. OSGOOD SHEET HANDLING APPARATUS 8 Sheets-Sheet Q 7 Filed Dec. 5, 1947 [menial '1' V Patented Aug. 14, 1951 UNITED STATES PATENT OFFICE SHEET HANDLING APPARATUS Rollin n. Osgood, Birmingham, Ala, assixnor to 'lennessee Coal, Iron and Railroad Company, a corporation of Alabama Application December 3, 1947, Serial No. 789,403

12 Claims.

This invention relates to plating lines for metal sheets, and particularly to improved apparatus and methods for handling and assorting sheets immediately following a plating operation.

The apparatus and methods of the present invention are especially suited for handling and assorting steel sheets that have been tin plated by hot-dip processes. Therefore the invention is described in connection with a hot-dip tinning line, but it is to be understood that the invention is not necessarily limited to such application.

The usual practice in hot-dip tinning includes passing steel sheets in multiple parallel rows through molten tin metal, hot palm oil and then through a branner, which removes all excess oil and polishes the tinned sheet. The tinned/sheets are then transported to an assorting room; where they are visually inspected and assorted as primes, menders, and waste-waste; Prime sheets are counted and stacked for shipment; menders are reprocessed to form primes, while waste-waste sheets are sold as an off grade prodnot.

In usual installations with which I am familiar, operations performed subsequent to tinning are largely manual, and consequently are time consuming and costly. Each sheet is handled individually during inspection and prime sheets are counted and stacked by hand. During tinning, the trailing or drip edge of each sheet becomes slightly thicker than the leading edge since a little more tin accumulates at the trailing edge. Consequently the workman who counts and stacks the sheets must stack them with the trailing and leading edges of each few sheets alternated in order to form a uniform stack.

An object of the present invention is to provide improved methods and apparatus for handling and visually inspecting sheets subsequent to plating wherein manual operations are substantially eliminated.

A further object of the invention is to provide a double hot-dip plating line embodying a novel combination of a visual inspection apparatus preceded by transfer apparatus for consolidating a pair of rows of plated sheets into a single row, whereby only one inspector and one inspection apparatus may inspect and assort a double line.

A further object of the invention is to provide improved plating lines for metal sheets embodying transfer apparatus for automatically reversing the original leading and trailing edges of a1- ternate sheets followed by apparatus for continuously asserting the sheets, whereby prime sheets emerging from the line are automatically arranged for uniform stacking without further handling.

A further object of the invention is to provide improved sheet transfer apparatus for consolidating sheets in a double hot-dip tinning line into a single row and reversing the original leading and trailing edges of alternate sheets from corresponding edges of the other sheets.

A further object of the invention is to provide improved sheet inspection apparatus wherein travel of sheets in a line is automatically arrested and the sheets are presented for visual inspection on both sides and manual handling during inspection is virtually eliminated.

A further object of the invention is to provide in plating lines for sheet metal an improved genus of apparatus for moving the sheets that comprises a rotatable sheet supporting device which is set in motion by approach of a sheet thereto, automatically moves the sheet through a predetermined angle, and then stops.

A further object of the invention is to provide improved methods for continuously assorting sheets as primes, menders, and waste-waste and arranging alternated sheets with the original leading and trailing edges reversed.

In accomplishing these and other objects of the invention I have provided improved details of construction, a preferred form of which is shown ment and embodying features of the present invention;

Figure 2 is a side elevational view of the line, partly in section, the view being taken on line IIII of Figure 1;

Figure 3 is an enlarged top plan view of a preferred construction of sheet transfer apparatus;

Figure 4 is an end elevational view of the transfer apparatus in the direction of arrow 4 in Figure 3;

Figure 5 is a vertical sectional view of the transfer apparatus taken substantially on line V--V of Figure 3;

Figure 6 is a horizontal sectional view of the transfer apparatus taken substantially on the line VI-VI of Figure 5;

Figure '7 is an electric wiring diagram of the control circuit for operating the transfer apparatus;

Figure 8 is an enlarged top plan view of a preferred construction of inspection apparatus;

Figure 9 is an enlarged side elevational view of the inspection apparatus;

Figure 10 is a vertical sectional View of the inspection apparatus taken substantially on line X-X of Figure 8;

Figure 11 is a vertical sectional view of the drive mechanism for the inspection apparatus taken substantially on line XI-XI of Figure 8;

Figure 12 is a vertical sectional view of the drive mechanism for the inspection apparatus taken substantially on line XII-XII of Figure 11; and

Figure 13 is an electric wiring diagram of the control circuit for operating the inspection apparatus.

Referring more in detail to the drawings:

In Figures 1 and 2 there are shown branner rolls l4 of hot-dip tin plating equipment from which plated sheets "S emerge for assorting and stacking. Sheets emerge from the plating equipment in two parallel rows and pass onto parallel horizontal conveyor belts I5 and I6. Said conveyors are supported on a frame l1 and are driven from a horizontal shaft l8 journalled in the lower portion of said frame. Shaft I8 is driven from branner roll I4 by a chain l9 and drives the conveyors through chains 20 and 2|, Figure 3.

The feeding rate is such that sheets on conveyor l6 are spaced by a little more than the length of an individual sheet. A transfer apparatus 22 lifts the sheets individually from conveyor I5 and places them on conveyor l6 within this space to form a consolidated single row of sheets on conveyor IS. The sheet in said single row are spaced at relatively close and substantially uniform intervals. The details of the transfer apparatus are fully described hereinafter.

From conveyor l6 sheets pass onto a conveyor 23, which is formed of a series of transversely spaced parallel belts 24. Said belts are supported on a frame 25, which has rearward rollers 26, intermediate rollers 21 and forward rollers 28 over which the belts pass. The axis of intermediate rollers 21 coincides with the axis of an inspection wheel 29 hereinafter fully described. Conveyor 23 is driven by a motor 36 which is supported on frame 25, and operatively connected with forward rollers 28.

From conveyor 23 the sheets traverse a series of conveyors which carry them past reject gates and to a mechanical counter and piler. The gates, counter and piler are of any suitable known construction. The mechanism beyond conveyor 23 is not per se a part of the present invention; hence its construction is not shown nor described in detail.

The operator visually inspects sheets as they pass inspection wheel 29, where their travel is temporarily arrested. In accordance with known practice. the operator closes a switch as he detects a mender" sheet and a different switch as he detects a waste-waste sheet. Closing said switches operates respective reject gates after a suitable timed interval such that the defective sheet is rejected to the proper group. Inasmuch as time delay mechanism for operating reject gates is known and per se is not part of the present invention, such mechanism is not shown nor described in detail.

The original leading and trailing edges of sheets transferred from conveyor l5 to conveyor |6 are reversed from the corresponding edges of untransferred sheetsso that, except for sheets rejected, the original leading and trailing edges of alternate sheets are reversed in the final stack. The rejection of a few sheets does not appreciably affect uniformity of the stack, and any unevenness tends to be compensated, since rejection may come from sheets ori inating from either row.

The mechanical construction of the rotatable sheet supporting device forming transfer apparatus 22 is shown in detail in Figures 3, 4, 5 and 6. The apparatus comprises a fixed frame 32 that straddles conveyors l5 and I6 and their supporting frame I1. Said frame includes uprights 33 and 34 at opposite sides of said conveyors and cross beams 35 and 36 fixed to said uprights and connected by short longitudinal members 31.

Frame 32 supports a magnetic turntable 38 and drive means therefor. As sheets emerge on conveyor l5, they engage and momentarily close a trigger switch 39, which actuates the turntable magnets to lift a sheet from the conveyor. At the same time the drive means for the turntable is actuated and the turntable automatically rotates through a substantially semi-circular arc and deposits the sheet on conveyor l6.

As shown in Figures 3 and 4, the drive for the turntable includes a motor 40 supported on cross beams 35 and 36. Motor 40 runs continuously and drives a worm 4|, which drives a worm gear- 42, Figure 5. The worm and worm gear are seated within a fixed housing 43 supported above beams 35 and 36 by legs 44 and 45.

Worm gear 42 is fixed to a vertical shaft 46, which carries an annular driving magnet 41 of a magnetic clutch at its lower end. The upper end of shaft 46 carries a pair of slip rings 48 and 49 for conducting current to'driving magnet 41. Driving magnet 41 is thus continuously rotated and, as hereinafter explained, it may be intermittently energized through slip rings 48 and 49.

An annular braking magnet 50 is fixed between beams 35 and 36 beneath driving magnet 41 and is axially aligned with shaft 46.

A vertical shaft 5|, axially aligned with shaft 46, is journaled in antifriction bearings 52 and 53. Said bearings are fixed to beams 35 and 36 and permit shaft 5| to have limited axial movement. A clutch plate 54 of magnetic material is fixed to the upper end of shaft 5| in the space between driving magnet 41 and braking magnet 56. Turntable 38 is fixed to the lower end of shaft 5|.

Turntable 38 carries electric transfer magnets 55 and 56 in diametrically opposed position at opposite sides of said shaft. As shown in Figure 4, the lower faces of magnets 55 and 56 are in close proximity to the upper faces of conveyors I5 and "5, but sufficient clearance is provided not to interfere with sheet movement. In order to lift thin sheets, magnets 55 and 56 preferably extend radially from a center point above the center of each sheet and have elongated radially extending poles.

As best shown in Figures 5 and 6, shaft 5| carries a cam ring 51 and slip rings 58 and 59 at its intermediate region between bearings 52 and 53. The cam ring has two segments of increased radius apart, one of which is shown at 66. Said segments operate a cam switch 6| to de-energize magnets 55 and 56 to deposit sheets on conveyor l6. The slip rings conduct current to magnets 55 and 56. The purpose and operation of these elements is more fully explained hereinafter in the description of the electric circuit.

For supporting cam switch 6|, frame member 85 carries a fixed bracket 52 on which is supported an arcuately adjustable yoke 85. Said yoke carries switch 6|, which has a roller 54 that rides against the surface of cam ring II, Figured. Cam switch BI is normally closed, but is opened momentaril while roller 54 engages one of the projecting segments 50 of cam ring 51.

Slip ring 58 comprises two substantially semicircular segments 65 and 68 separated by insulators 61 and 68, Figure 6. Yoke 53 carries a pair of brushes 59 and I engaging segments 85 and 55, the brushes preferably bein mounted for arcuate adjustment with respect to the yoke. Slip ring 59 is circular and continuous, and yoke 68 carries a brush II which contacts slip ring 59.

A downwardly depending boss I2 is fixed to yoke 53 and has a transverse threaded bore. A threaded spindle I9 is journaled in a fitting I4 which is pivoted to bracket 82, as indicated at 15, Figure 6, to permit arcuate movement of the spindle. Said spindle is threadedly engaged within the transverse bore through boss I2 and carries a knob I6 accessible externally of the apparatus. Thus rotation of knob I adjusts yoke 55 arcuately about vertical shaft 5|.

The control circuit for operating the transfer apparatus is shown in Figure 7. The circuit includes four relays whose coils are indicated at A, B, C and D. The contacts of each relay are indicated by the same letters with appropriate subscripts.

The circuit includes conductors I1 and I8 connected to a suitable outside power source. Preferably a master switch I9 is provided for manu ally opening and closing the circuit to said conductors.

A conductor 88 is connected across conductors I1 and I8 and contains relay coil C, contacts BI and cam switch 8|. A conductor 8| is connected to conductor 11 and to conductor 85 shunting relay coil C and contacts BI. Conductor 8| contains relay coil A and trigger switch 99 which, as shown in Figure 3, is positioned in the path 'of sheets on conveyor l5 to be closed momentarily as each sheet passes on said conveyor.

Closin of the trigger switch energizes relay coil A, since cam switch 8| is normally closed. Energization of relay coil A closes contacts Al which seals in relay coil A, shunting trigger switch 39. At the same time, contacts A2 are closed to provide a current path to segment 85 of slip ring 58 via a conductor 82 and brush 89. Transfer magnet is connected between segment and slip ring 59. Brush II, which contacts slip ring 59, is connected to conductor I8 55 through a conductor 83. Thus when contacts A2 are closed, transfer magnet 55 is energized via conductor 11, contacts A2, conductor 82, brush 59, slip ring segment 55, magnet 55, slip ring 59,

brush II, conductor 89 and conductor I8. The to sheet is thereupon lifted from conveyor l5.

Closing of contacts A2 also completes a circuit to relay coil B through normally closed relay contacts DI and through a conductor 84 connected to the conductor intermediate coil C and 05 cam switch 6 I. Energization of coil B closes contacts Bl in conductor 88 and thereby energizes relay coil C. Energizing coil C closes contacts CI, which seal in coil B via contacts A2 and 0|, thus shunting contacts D|.

At the same time, energizing coil C closes contacts C2 which are in conductor II. The terminus of conductor 11 is connected to a brush 85 that engages slip ring 48 at the top of vertical magnet 41 and the opposite end of said driving magnet is connected to slip ring 49. The terminus of conductor I8 is connected to a brush 86 that engages slip ring 49. Energization of coil 0 also opens contacts C3 which are in a conductor 81 which extends between conductors II and I8 and contains braking magnet 58. Thus driving magnet 41 is energized and lifts clutch plate 54 and commences rotation of shaft 5| and tumtable 88.

Rotation of shaft 5| rotates slip ring 58 in the direction indicated in Figure 7. After said slip ring is rotated a predetermined distance, brushes i9 and I0 both contact the same segment 55, which forms a current path between them. Brush I0 is connected by a conductor 88 to a timer 89. Said timer is connected to relay coil D through a conductor 90 and relay coil D is connected to conductor I8 through a conductor 9|. When brushes 89 and I8 both contact segment 65, a circuit is completed through timer 89 and relay coil D via conductor 11, contacts A2; conductor 82, brush 59, segment 65, brush I0, conductor 88, timer 89, conductor 90, coil D, conductor 9| and conductor I8. Timer 89 contains a mechanism which immediately completes the circuit through coil D and holds said circuit closed for a predetermined interval and then opens the circuit. Inasmuch as such timing mechanism is known and per se does not form a part of the present invention, the details are not shown. Energize.- tion of coil D opens contacts DI and closes contacts D2, the latter sealing in the circuit through timer 89 and coil D.

Continued rotation of shaft 4| moves one of the projecting cam segments 50 to a position where it momentarily opens cam switch 6|. Opening this switch breaks the circuit through conductor 88 and thus deenergizes coils A, B, and C. Contacts C2 thereupon open and interrupt the circuit to drivin magnet 41. Contacts D2 remain closed and contacts C3 are closed by deenergization of coil C. Thus the circuit to braking magnet 58 is closed. The arrangement is such that cam switch 6| opens about 5 before turntable 38 has rotated 180 so that the tumtable comes to rest after rotating exactly 180. Necessary adjustments in the point at which the turntable stops may be made through adjustment of spindle I3, which varies the position of the cam switch with respect to the 180 point.

The transfer magnets are kept energized momentarily after the turntable has stopped. The circuit by which magnet 55 is energized at this time is via conductor II, contacts D2, conductor 88, brush I9, segment 85, magnet 55, slip ring 59. brush II, conductor 83, and conductor I8. As soon as the predetermined interval has elapsed. timer 89 opens the circuit to coil D, which opens contacts D2 and thereby deenergizes the trans fer magnets. The magnets thereupon deposit the sheet on conveyor Hi. The apparatus is now in position for the opposite transfer magnets 56 to move a sheet from conveyor I5 to conveyor l6 and the cycle of operations just described is repeated, except that magnets 55, segment 85 and the other cam segment 60 are now operative.

Preferably braking magnet 58 is shunted by a high resistance 92 and a condenser 93, and driving magnet 41 is shunted by a similar resistance and condenser 94 and 95 respectively. The purpose of these shunts is to prevent arcing when the circuits to the magnets are broken.

shaft 46. Said slip ring is connected to driving 75 This .type of shunting arrangement is a known device for preventing arcing and hence is not described in detail.

Preferably a push button position switch 99 is connected around trigger switch 39 and cam switch SI so that the apparatus may be energized manually for testing and adjustment. It is seen that closing switch 96 has the same effect as closing trigger switch 39.

The mechanical details of the rotatable sheet supporting device forming inspection wheel 29 are best shown in Figures 9, 10, 11 and 12. Said wheel comprises six sets of parallel radial spokes 98 fixed to hubs 99, the spokes of each set being spaced 60 from theadjacent set. Hubs 99 are fixed to a horizontal shaft I and spaced longitudinally of said shaft so that a set of spokes is positioned between each pair of belts 24 that make up conveyor 23. Intermediate the hubs, shaft I00 carries rollers 21 over which pass belts 24 of conveyor 23. Shaft I00 is journaled in bearings WI and I02 fixed to frame 25. Drive mechanism is provided so that each sheet entering the wheel from conveyor 23 momentarily closes a trigger switch I03 and rotates wheel 29 through an angle of 60.

' The sheet that has entered the wheel thereupon is moved to the position shown in full lines in Figure and its travel temporarily arrested. With the sheet so positioned, the inspector may readily examine the upper surface. The inspector then manually flips the sheet to the position shown in dot-dash lines in Figure 10 and examines the other surface. Presently conveyor 23 carries another sheet into the wheel, whereupon the wheel rotates another 60. On one more movement of the wheel, the inspected sheet is picked up by the forward section of conveyor 23 and carried to the piler or diverted by one of the reject gates.

The adjustment of wheel 29 is such that the wheel comes to rest following each 60 advance when the spokes in the forward and rearward positions are horizontal. As shown in Figures 9 and 10, in the position of rest the upper faces of the rearward spokes are slightly below the upper faces of belts 24 of conveyor 23 in order that sheets entering the wheel do not scrape across the spoke faces. of conveyor 23 is downwardly inclined at an angle such that the forward section is intermediate two sets of spokes when the wheel is stopped. Asthe segment of the wheel containing an inspected sheet rotates past the inclined forward section, said section picks up the sheet and the spokes move cleanly away so that again there is no scraping.

Sheets deposited on the downwardly inclined conveyor section tend to slide down said section, and thus to upset timing of the reject gates. In order to prevent such sliding, magnets I04 are arranged underneath the belts of the inclined conveyor section, preferably being permanentmagnets and encased in suitable fixed housings I05.

As shown in Figure 10, the intersection of adjacent sets of spokes 98 is preferably at a sharp angle and the faces of the spokes preferably form a substantially plane surface. This arrangement is desirable in order that the sheet is fiat while undergoing inspection and does not distort light reflections. Thus the inspector is enabled to determine more accurately whether there are imperfections in the sheet.

The inspection wheel is preferably driven by a magnetic clutch arrangement similar to that for Preferablythe forward section' ,suitable outside power source.

' trigger switch driving the-transfer apparatus. The drive is from a motor I00 which is supported on frame 25 and continuously drives a speed reducing gear I01 through a suitable coupling, Figure 8. Gears I01 continuously rotate a shaft I08, the inner extremity of which carries an annular driving magnet I09 of the magnetic clutch, Figure 11. A horizontal shaft I I0, axially aligned with shaft I08, is journaled in suitable bearings III and 2 on frame 25 and has limited axial movement. The outer end of shaft I I0 carries a clutch plate II3 adjacent driving magnet I09. An annular braking magnet I I4 is positioned adjacent clutch plate II3 on the opposite side from said driving magnet.

Shaft I I0 carries a pinion II5 which meshes with a gear I I6'on shaft I00 on which hubs 99 of wheel 29 are mounted, Figure 8. Preferably the ratio of pinion H5 and gear H6 is 1 to 6 so that. each whole revolution of shaft IIO rotates wheel 29 through an angle of Shaft IIO carries a cam ring II! which has an enlarged sector bracket H9 is fixed on a base I20 beneath said cam ring and supports an arcuately adjustable of spindle I24. Thus rotation of said spindle adjusts yoke I2I about the axis of shaft IIO. This adjustment varies the position at which cam sector IIB opens cam switch I22 and thus controls the angular position at which wheel 29 comes to rest.

The outer extremity of shaft I08 rings I28 and I29 for energizing driving magnet I09, Figures 8 and 11.

The control circuit for operating the inspection wheel is shown in Figure 13. The circuit.

includes conductors I30 and I3I connected to a Preferably said conductors include a master switch I32 for manually opening and closing the circuit. Conductors I30 and I 3| are connected through a conductor I33 that contains trigger switch I03, cam

. switch I22 and the coil of a relay E. Closing of I03 energizes coil E since cam switch I22 is normally closed.

Energization of coil E closes contacts EI which seal in coil E. Contacts E2 are also closed and .complete a circuit to driving magnet I09 via a conductor I34, a brush I35, slip ring I28, driving magnet I09, slip ring I29, a brush I36, and a conductor I31 to conductor I3I. At the same time, normally closed contacts E3 open and thus interruptthe circuit to braking magnet II4.

Thus shaft H0 and inspection wheel 29 are set in motion.

Continued rotation of shaft IIO moves cam Ill to a position where its enlarged sector II8 opens cam switch I22, whereupon the circuit to coil E is broken. Contacts E2 are opened, interruptin the circuit to the driving magnet and contacts E3 are closed, completing the circuit to the braking magnet. The adjustment of yoke I2I is such that shaft I I0 is stopped after one complete revo- II8, Figures 11 and 12. A

carries slip lution, which is equivalent to $4 of a revolution of the inspection wheel.

Preferably driving magnet I09 is shunted by a relatively high resistance I38 and a condenser I39 and braking magnet H4 is shunted by a similar resistance and condenser I40 and HI respectively. The resistance and condenser prevent arcing similar to corresponding elements in the transfer apparatus circuit.

Preferably a jog relay J and double pole jog push button switch I42 are provided for rotating inspection wheel 29 by manual actuation when desired. Jog relay J is connected across conductors I30 and I3I in a conductor I43. Switch I42 has a first pair of poles I44 in conductor I43 and a second pair of poles I in a parallel conductor I46, which also contains normally closed contacts JI Closing of switch I42 completes a circuit to coil E via conductor I46, poles I45 and normally closed contacts J I. Energization of coil E closes contacts EI which seal in coil E through cam switch I22. Contacts E4 in conductor I43 thereupon close, and poles I44 of switch I42 close at the same time poles I45 close and complete a circuit through jog relay coil J. Completing this circuit closes contacts J2 which seals in coil J as long as push-button I42 is held closed. When relay coil J is energized, contacts J I open, breaking the circuit through switch I 42 and contacts J I through coil E. When cam switch I22 opens, coil E is deenergized and opens, stopping the inspection wheel. Thus switch I42 must be opened and reclosed to operate the inspection wheel manually another notch and another spoke.

From the foregoing description it is seen that the plating line of the present invention consolidates multiple rows of sheets from the plating equipment into a single row. The original leading and trailing edges of alternate sheets in the single row are reversed so that the sheets may be stacked uniformly as they come from the row. Consolidation of the multiple rows enables inspection and asserting to be conducted from a single station without interrupting continuous movement of the line. Thus the transfer apparatus and the inspection apparatus cooperate and form a novel combination that makes possible continuous assorting and stacking of sheets from a multiple line without additional handling.

The method of continuously assorting and stacking sheets disclosed herein is not claimed in the present application for the reason that it forms the subject matter of a divisional application Serial No. 211,284, filed February 16, 1951. The inspection apparatus is not claimed in the present application for the reason that it also forms the subject matter of a divisional application Serial No. 211,283, filed February 16, 1951.

While I have shown and described but a single embodiment of the present invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited by the disclosure set forth but only by the scope of the appended claims.

I claim:

1. In a plating line for metal sheets, means for conveying sheets in a pair of parallel rows from the plating equipment, the sheets being slightly thicker at the trailing edge than at the leading edge, the sheets in each row being spaced a distance greater than a sheet length, and means for transferring the sheets individually from one of said rows into the spaces of the other row thereby forming a consolidated single row, said transi0 ferring means reversing the thirmer leading edges and the thicker trailing edges of transferred sheets from the corresponding edges of untransferred sheets, whereby the sheets may be stacked uniformly as they come from said single row.

2. In a plating line for metal sheets. means for conveying sheets in multiple rows from the plating equipment, the sheets being slightly thicker at the trailing edge than at the leading edge, the sheets in each row being spaced a distance greater than a sheet length, and rotatable magnetic means for lifting the sheets individually from one of said rows and placing them in the spaces of the other row thereby forming a consolidated single row, the thinner leading edges and the thicker trailing edges of sheets thus placed in said single row being reversed.

3. In a plating line for metal sheets, means for conveying sheets in a pair of parallel rows from the plating equipment. the sheets being slightly thicker at-the trailing edge than at the leading edge, the sheets in the rows being spaced a distance greater than a sheet length, and magnetic means rotatable on an axis between said rows for lifting sheets individually from one of said rows, carrying the sheet through a substantially semicircular arc, and placing it in a space of the other row, thereby forming a consolidated single row of sheets with the original leading and trailing edges of alternate sheets reversed.

4. In a plating line for metal sheets, means for conveying sheets in a pair of substantially horizontal parallel rows from the plating equipment, the sheets being slightly thicker at the trailing r edge than at the leading edge, the sheets in the I solidated single row of sheets with the original leading and trailing edges of alternate sheets reversed.

5. In a plating line for metal sheets, means for conveying sheets from the plating equipment in a pair of rows, a turntable 'rotatable on an axis between said rows, electromagnets carried by said turntable and adapted to overlie said rows, means for driving said turntable, electric switch means in the path of one of said rows adapted to be actuated by a sheet traveling therein, actuation of said switch means energizing, the 'electromagnet over the actuating sheet and thereby lifting the sheet and initiating rotation of said turntable by said drive means, and means stopping said turntable and de-energizing said electromagnet when the sheet is over the other row.

6. In a plating line for metal sheets, a pair of conveyors for conveying sheets from the plating equipment, a turntable rotatable on an axis between said conveyors, electromagnets carried by diametrically opposed portions of said turntable and adapted to overlie said conveyors, means for driving said turntable, electric switch means in the path of one of said conveyors adapted to be actuated by travel of a sheet thereon, actuation of said switch means energizing the electromagnet over the actuating sheet and thereby lifting the sheet and initiating rotation of said turntable by said driving means, and means stopping said turntable and de-energizing said electromagnet when the sheet is over the other conveyor.

7. In a plating line for metal sheets, a pair of substantially horizontal parallel conveyors for conveying sheets from the plating equipment, a turntable above said conveyors and rotatable on a vertical axis therebetween, electromagnets carried by diametrically opposed portions of said turntable and adapted to overlie said conveyors. means for driving said turntable, electric switch means in the path of one of said conveyors adapted to be actuated by travel of a sheet thereon, actuation of said switch means energizing the electromagnet over. the actuating sheet and thereby lifting the sheet and initiating rotation of said turntable by said driving means, and means stopping said turntable and de-energizing said eleetromagnet when the sheet is over the other conveyor.

8. In a plating line for metal sheets, a pair of substantially horizontal parallel conveyors for conveying sheets from the plating equipment, a turntable above said conveyors and rotatable on a vertical axis therebetween, electromagnets carried by diametrically opposed portions of said turntable, means for driving said turntable and including a magnetic clutch, electric switch means in the path of one of said conveyors adapted to be actuated by travel of a sheet thereon, actuation of said switch means energizing the electromagnet over the actuating sheet and said magnet clutch, thereby lifting the sheet and initiating rotation of said turntable by said driving means, and means stopping said turntable and de-energizing said electromagnet when the sheet is over the other conveyor.

9. In a plating line for metal sheets, a pair of substantially horizontal parallel conveyors for conveying sheets from the plating equipment, a turntable above said conveyors and rotatable on a vertical axis therebetween, electromagnets carried by diametrically opposed portions of said turntable, means for driving said turntable and including a magnetic clutch, electric switch means in the path of one of said conveyors adapted to be actuated by travel of a sheet thereon, actuation of said switch means energizing the electromagnet over the actuating sheet and said magnetic clutch, thereby lifting the sheet and initiating rotation of said turntable by said driving means, and additional electric switch means adapted to be actuated by rotation of said turntable through a substantially semi-circular arc, actuation of said additional switch means stopping said turntable and de-energizing said electromagnet when the sheet is over the other con veyor.

10. A transfer apparatus comprising a turntable rotatable on a vertical axis, electromagnets carried by diametrically opposed portions of said turntable, drive means adapted to be driven continuously, a magnetic clutch for connecting said turntable and said drive means and thereby rotating said turntable, means for energizing one of said electromagnets and engaging said magnetic clutch, thereby lifting an article and initiating rotation of said turntable, and means for deenergizing the electromagnet and disengaging said magnetic clutch after said turntable rotates through a predetermined are.

11. A transfer apparatus comprising a turntable, a shaft supporting said turntable and rotatable on a vertical axis, electromagnets carried by diametrically opposed portions of said turntable drive meansadapted to be driven continuously, a magnetic clutch for connecting said shaft and said drive means and thereby rotating said turntable, means for energizing one of said electromagnets and engaging said magnetic clutch, thereby lifting an article and initiating rotation of said turntable, electric switch means for subsequently de-energizing the electromagnet and disengaging said magnetic clutch, and means on said shaft for actuating said switch means after said turntable rotates through a predetermined arc.

12. A transfer apparatus comprising a tumtable, a rotatable shaft supporting said turntable, drive means adapted to be driven continuously, a magnetic clutch for connecting said shaft and said drive means, means for engaging said magnetic clutch and thereby initiating rotation of said turntable, a cam carried by said shaft, an arcuately adjustable yoke substantially surrounding said shaft, a switch carried by said yoke and adapted to be actuated by said cam, actuation of said switch disengaging said magnetic clutch and stopping of said turntable after rotation through a predetermined arc. and means on said turntable for carrying articles.

ROLLIN D. OSGOOD.

REFERENCES CITED The following references are of record in the file of this patent:

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